315 lines
12 KiB
Groff
315 lines
12 KiB
Groff
.\"-
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.\" Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
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.\" All rights reserved.
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.\""
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer,
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.\" without modification.
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.\" 2. Redistributions in binary form must reproduce at minimum a disclaimer
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.\" similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
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.\" redistribution must be conditioned upon including a substantially
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.\" similar Disclaimer requirement for further binary redistribution.
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.\" 3. Neither the names of the above-listed copyright holders nor the names
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.\" of any contributors may be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\"
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.\" NO WARRANTY
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.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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.\" LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
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.\" AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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.\" THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
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.\" OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
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.\" IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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.\" THE POSSIBILITY OF SUCH DAMAGES.
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.\"
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.\" $FreeBSD$
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.\"/
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.Dd July 13, 2003
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.Dt ATH 4
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.Os
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.Sh NAME
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.Nm ath
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.Nd "Atheros IEEE 802.11 driver"
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.Sh SYNOPSIS
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.Cd "device ath"
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.Sh DESCRIPTION
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The
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.Nm
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driver provides support for wireless network adapters based on
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the Atheros AR5210, AR5211, and AR5212 chips.
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Chip-specific support is provided by the Atheros Hardware Access Layer
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(HAL), that is packaged separately.
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.Pp
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Supported features include 802.11 and 802.3 frames, power management, BSS,
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IBSS, and host-based access point operation modes.
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All host/device interaction is via DMA.
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.Pp
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The
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.Nm
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driver encapsulates all IP and ARP traffic as 802.11 frames, however
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it can receive either 802.11 or 802.3 frames.
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Transmit speed and operating mode is selectable
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depending on your hardware.
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AR5210-based devices support 802.11a operation with trasmit speeds
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of 6 Mbps, 9 Mbps, 12 Mbps, 18 Mbps, 24 Mbps, 36 Mbps, 48 Mbps, and 54 Mbps.
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AR5211-based devices support 802.11a and 802.11b operation with transmit
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speeds as above for 802.11a operation and
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1Mbps, 2Mbps, 5.5 Mbps and 11Mbps for 802.11b operation.
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AR5212-based devices support 802.11a, 802.11b, and 802.11g operation
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with transmit speeds appropriate to each.
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All chips also support an Atheros Turbo Mode (TM) that operates in the 802.11a frequency range with 2x the transmit speeds.
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(This mode is, however, only interoperable with other Atheros-based devices.)
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The actual transmit speed used is dependent on signal quality and the
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``rate control'' algorithm employed by the driver.
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All chips support WEP encryption.
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AR5211 and AR5212 support the AES, TKIP, and Michael cryptographic
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operations required for WPA but at this time the driver does not support them.
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To enable encryption, use
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.Xr ifconfig 8
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as shown below.
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.Pp
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By default, the
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.Nm
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driver configures the card for BSS operation (aka infrastructure
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mode).
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This mode requires the use of an access point (base station).
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.Pp
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The
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.Nm
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driver also supports the standard IBSS point-to-point mode
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where stations can communicate amongst themselves without the
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aid of an access point.
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.Pp
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The driver may also be configured to operate in hostap mode.
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In this mode a host may function as an access point (base station).
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Access points are different than operating in IBSS mode.
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They operate in BSS mode.
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They allow for easier roaming and bridge all ethernet traffic such
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that machines connected via an access point appear to be on the local
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ethernet segment.
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.Pp
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For more information on configuring this device, see
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.Xr ifconfig 8 .
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.Pp
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Devices supported by the
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.Nm
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driver come in either Cardbus or mini-PCI packages.
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Wireless cards in Cardbus slots may be inserted and ejected on the fly.
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.Pp
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The following cards are among those supported by the
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.Nm
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driver:
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.Pp
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.Bl -column -compact "D-Link DWL-AG650" "AR5212" "Cardbus"
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.Em "Card Chip Bus"
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D-Link DWL-AB650 AR5211 Cardbus
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D-Link DWL-AG520 AR5212 PCI
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D-Link DWL-AG650 AR5212 Cardbus
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Linksys WMP55AG AR5212 PCI
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Linksys WPC51AB AR5211 Cardbus
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Linksys WPC55AG AR5212 Cardbus
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Netgear WAB501 AR5211 Cardbus
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Netgear WAG511 AR5212 Cardbus
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.El
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.Sh EXAMPLES
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Join an existing BSS network (ie: connect to an access point):
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.Pp
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.Dl "ifconfig ath0 inet 192.168.0.20 netmask 0xffffff00"
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.Pp
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Join a specific BSS network with network name
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.Dq Li my_net :
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.Pp
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.Dl "ifconfig ath0 inet 192.168.0.20 netmask 0xffffff00 ssid my_net"
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.Pp
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Join a specific BSS network with WEP encryption:
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.Bd -literal -offset indent
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ifconfig ath0 inet 192.168.0.20 netmask 0xffffff00 ssid my_net \e
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wepmode on wepkey 0x8736639624
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.Ed
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.Pp
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Join/create an 802.11b IBSS network with network name
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.Dq Li my_net :
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.Bd -literal -offset indent
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ifconfig ath0 inet 192.168.0.22 netmask 0xffffff00 ssid my_net \e
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mode 11b mediaopt adhoc
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.Ed
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.Pp
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Create an 802.11g host-based access point:
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.Bd -literal -offset indent
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ifconfig ath0 inet 192.168.0.10 netmask 0xffffff00 ssid my_ap \e
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mode 11g mediaopt hostap
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.Ed
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.Pp
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Create an 802.11a host-based access point with WEP enabled:
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.Bd -literal -offset indent
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ifconfig ath0 inet 192.168.0.10 netmask 0xffffff00 ssid my_ap \e
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wepmode on wepkey 0x1234567890 mode 11a mediaopt hostap
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.Ed
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.Pp
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Create a host-based wireless bridge to fxp0:
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.Bd -literal -offset indent
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Add BRIDGE to the kernel config.
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ifconfig ath0 inet up ssid my_ap media DS/11Mbps mediaopt hostap
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sysctl net.link.ether.bridge=1
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sysctl net.link.ether.bridge_cfg="ath0 fxp0"
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sysctl net.inet.ip.forwarding=1
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.Ed
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.Pp
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This will give you the same functionality as an access point.
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.Sh DIAGNOSTICS
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.Bl -diag
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.It "ath%d: unable to attach hardware; HAL status %u"
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The Atheros Hardware Access Layer was unable to configure the hardware
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as requested.
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The status code is explained in the HAL include file
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.Pa sys/contrib/dev/ath/ah.h .
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.It "ath%d: failed to allocate descriptors: %d"
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The driver was unable to allocate contiguous memory for the transmit
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ad receive descriptors.
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This usually indicates system memory is scarce and/or fragmented.
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.It "ath%d: unable to setup a data xmit queue!"
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The request to the HAL to setup the transmit queue for normal
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data frames failed.
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This should not happen.
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.It "ath%d: unable to setup a beacon xmit queue!"
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The request to the HAL to setup the transmit queue for 802.11 beacon frames
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frames failed.
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This should not happen.
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.It "ath%d: 802.11 address: %s"
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The MAC address programmed in the EEPROM is displayed.
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.It "ath%d: hardware error; resetting"
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A nunrecoverable error in the hardware occurred.
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Errors of this sort include unrecoverable DMA errors.
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The driver will reset the hardware and continue.
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.It "ath%d: rx FIFO overrun; resetting"
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The receive FIFO in the hardware overflowed before the data could be
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transferred to the host.
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This typically occurs because the hardware ran short of receive
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descriptors and had no place to transfer received data.
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The driver will reset the hardware and continue.
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.It "ath%d: unable to reset hardware; hal status %u"
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The Atheros Hardware Access Layer was unable to reset the hardware
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as requested.
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The status code is explained in the HAL include file
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.Pa sys/contrib/dev/ath/ah.h .
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This should not happen.
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.It "ath%d: unable to start recv logic"
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The driver was unable to restart frame reception.
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This should not happen.
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.It "ath%d: device timeout"
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A frame dispatched to the hardware for transmission did not complete in time.
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The driver will reset the hardware and continue.
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This should not hapen.
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.It "ath%d: bogus xmit rate 0x%x"
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An invalid transmit rate was specified for an outgoing frame.
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The frame is discarded.
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This should not happen.
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.It "ath%d: ath_chan_set: unable to reset channel %u (%u Mhz)"
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The Atheros Hardware Access Layer was unable to reset the hardware
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when switching channels during scanning.
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This should not happen.
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.It "ath%d: unable to allocate channel table"
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The driver was unable to allocate memory for the table used to hold
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the set of available channels.
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.It "ath%d: unable to collect channel list from hal"
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A problem occurred while querying the HAL to find the set of available
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channels for the device.
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This should not happen.
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.It "ath%d: %s: %dM -> %dM (%d ok, %d err, %d retr)"
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The driver's rate control algorithm changed the current rate for transmitting
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frames.
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This message is temporarily enabled for normal use to help in diagnosing
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and improving the rate control algorithm.
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The message indicates the new and old transmit rates and the statistics
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it used to decide on this change.
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.It "ath%d: failed to enable memory mapping"
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The driver was unable to enable memory-mapped I/O to the PCI device registers.
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This should not happen.
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.It "ath%d: failed to enable bus mastering"
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The driver was unable to enable the device as a PCI bus master for doing DMA.
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This should not happen.
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.It "ath%d: cannot map register space"
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The driver was unable to map the device registers into the host address space.
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This should not happen.
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.It "ath%d: could not map interrupt"
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The driver was unable to allocate an IRQ for the device interrupt.
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This should not happen.
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.It "ath%d: could not establish interrupt"
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The driver was unable to install the device interrupt handler.
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This should not happen.
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.El
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.Sh SEE ALSO
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.Xr an 4 ,
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.Xr arp 4 ,
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.Xr ath_hal 4,
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.Xr card 4 ,
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.Xr netintro 4 ,
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.Xr pcic 4 ,
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.Xr wi 4 ,
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.Xr wlan 4 ,
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.Xr ifconfig 8 ,
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.Xr wicontrol 8
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.Re
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.Sh HISTORY
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The
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.Nm
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device driver first appeared in
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.Fx 5.2 .
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.Sh CAVEATS
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Different regulatory domains have different default channels for adhoc
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mode.
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See
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.Xr ifconfig 8
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for information on how to change the channel.
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See
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.Xr wicontrol 8
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for information on different regulatory domains.
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.Pp
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802.11g support is little tested and may have interoperabity problems.
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The software is known to function with an Atheros 11g access point but
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interoperability may be problematic until vendors update firmware in
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existing 11g products.
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If you encounter problems using an 11g access point you should be able
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to workaround incompatibilities by locking the driver to 11b mode.
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Alternatively, most 11g compatibility issues are in the 802.11 layer
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and you may be able to workaround issues by modifying the
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.Xr wlan 4
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module.
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.Pp
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Atheros Turbo mode is untested.
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.Sh BUGS
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.Pp
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Roaming mode is broken.
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If you lose your access point by going out of
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range the driver does not automaticaly re-associate.
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.Pp
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Adhoc mode is untested and possibly/probably broken.
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.Pp
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Performance in lossy environments is suboptimal.
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The algorithm used to select the rate for transmitted packets is
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very simplistic.
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There is no software retransmit; only hardware retransmit is used.
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Contributors are encouraged to replace the existing rate control algorithm
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with a better one (hint: all the information needed is availble to the driver).
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.Pp
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General performance is suboptimal.
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The Atheros hardware is known to be capable of transfer rates of 23-34 Mb/s
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(or more) in 11a and 11g modes using their NDIS (aka Windows) driver.
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Results with this driver are mixed and seem to vary significantly.
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.Pp
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It has been observed that getting a DHCP address sometimes requires
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multiple tries.
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This seems to happen only with AR5211 and AR5212 parts and mostly
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in a noisy environment (i.e. one where many access points are found).
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This problem is specific to the driver and not the hardware.
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.Pp
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The driver does not fully enable power-save operation of the chip;
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consequently power use is suboptimal.
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